1. Field of the Invention
This invention relates generally to preparation of shaped articles, such as food products, medicaments and the like, which comprise one or more ingestible substances enclosed in another ingestible substance. More particularly, this invention relates to extrusion apparatus for producing such shaped articles.
2. Prior Art
Products having a central filling material partially or wholly enclosed in an outer layer of a different material (e.g., food products and medicaments) are well known in the art. Examples of such products include tamales, ravioli, dumplings, pierogi, filled donuts, gelatin-coated pharmaceuticals, "soft-center" candies, and the like. Numerous devices have been developed in an attempt to facilitate the rapid production of such articles in large quantities. In general, such devices have included: (1) source means for supplying the inner and outer materials which are, at least initially, in a moldable or extrudable form; (2) means, generally in the form of concentric nozzle elements, for selectively continuously extruding and shaping the materials; and, (3) means for separating the shaped articles from the mass of materials supplied through the extruding means.
Typical examples of such devices are illustrated in U.S. Pat. Nos. 2,575,921; 3,615,147; 3,679,338; 3,778,209; 4,015,518 and 4,028,024. The prior art devices are, in general, quite complex, costly to construct and difficult to operate. As a result they are frequently limited to use in large scale processing "plants where skilled operators and repair personnel are available. Despite a well-recognized consumer preference for freshly-made foods, there is little likelihood that such devices could be economically installed and employed in production of shaped articles at, for example, a restaurant. Furthermore, such prior art devices generally do not permit easy alteration of the size and/or shape of the article to be formed without extensive modifications and changes in machine parts such as extrusion dies, and the like.